The present invention relates generally to semiconductor manufacturing, and more particularly to a program and method for generating a semiconductor test first pass yield report.
In the semiconductor industry there is a continuing trend toward high line rate production of integrated circuit products. In order to achieve high quantity production as well as quality assurance, there have been, and continue to be, efforts toward providing automated testing of production parts as well as detailed analysis of test results. The production of semiconductor integrated circuits typically involves a multi-step manufacturing process in which defects or errors may be introduced into a product at one or more steps in the process. Manufacturing and process engineers study the defect rates and product yields as well as the efficiency associated with such multi-step manufacturing processes and the individual steps therein, in order to determine where changes in a process may improve the product, reduce cost, save time, and the like. In particular, the initial or first run of a given manufacturing process needs to be carefully scrutinized so that any necessary adjustments may be made prior to approving the process for further production.
Another trend in the semiconductor industry is the reduction of feature sizes and an increase in device density in integrated circuit products. Such features may include the width and spacing of interconnecting lines and the surface geometry such as the corners and edges of various features. The requirement of small features with close spacing between adjacent features requires high resolution photo lithographic processes. In general, lithography refers to processes for pattern transfer between various media. It is a technique used for integrated circuit fabrication in which, for example, a silicon wafer is coated uniformly with a radiation-sensitive film (e.g, a photoresist), and an exposing source (such as ultraviolet light, x-rays, or an electron beam) illuminates selected areas of the film surface through an intervening master template (e.g., a mask or reticle) to generate a particular pattern. The exposed pattern on the photoresist film is then developed with a solvent called a developer which makes the exposed pattern either soluble or insoluble depending on the type of photoresist (i.e., positive or negative resist). The soluble portions of the resist are then removed, thus leaving a photoresist mask corresponding to the desired pattern on the silicon wafer for further processing.
In addition to reduced feature sizes and device density increases, the introduction of larger and larger wafers makes defects in a single wafer potentially more costly than that of a smaller wafer. Thus, as more components may be included within a given high device density semiconductor wafer, and as the size of the wafers increases, the detection of manufacturing process defects becomes more critical. Accordingly, various inspection tools, such as those commercially available from KLA-Tencor, Orbot, and Inspex, have been developed to map and record wafer surface features and other defects. The timely and thorough analysis of test data obtained through such inspection equipment is important for quality assurance as well as for achieving and maintaining high production rates for such high density semiconductor wafers.
Various testing instruments and equipment are typically employed in the manufacture of semiconductor devices, some of which may be made by different vendors. Each piece of test equipment makes measurements of specific features or performance indicia in the manufactured devices. For example, test equipment may be used to selectively verify shorts and opens between various nodes in an integrated circuit device. The correlation of the measured shorts and opens in a given die or device within a semiconductor wafer with those of a known good device may be used to indicate whether a device or circuit under test is defective. Where a batch of such devices is processed according to a multi-step manufacturing process, the yield of acceptable products may be advantageously monitored by production personnel in order to make necessary adjustments in one or more steps in the process in order to minimizing defects and down time.
Where a new or modified process is employed for the first time, the yield results may be closely scrutinized. However, the gathering of such first pass yield result data, and the sorting of such into useable form for engineering analysis takes time, during which the process may be continued (potentially at the risk of producing further defects), or the process may be interrupted pending data analysis. Thus, timely gathering, assembly, sorting, formatting, and calculation of such information is desirable. Heretofore, these tasks have been largely performed manually. For instance, process and manufacturing engineering personnel typically download individual sets of raw data from various test equipment into a spreadsheet computer software application. Thereafter, unwanted data is manually deleted, and sorting, reformatting, and computations are performed in order to present the yield results in a useable form for engineering analysis. Due to the increased cost of manufacturing down time, as well as the increased cost of high density semiconductor wafer defects, there remains a need for improved methods and systems for expeditiously generating yield reports.
The present invention provides a software macro or program and methodology for automated generation of yield reports. The invention finds particular utility in association with the manufacture and testing of semiconductor integrated circuits, although other applications are possible within the scope of the invention. The invention further includes a computer system for generating a yield report. According to one aspect of the invention, there is provided a method of generating a semiconductor manufacturing test first pass yield report, which comprises obtaining raw data from one or more workstream databases into a spreadsheet software application in a computer system, executing a software macro for formatting and sorting the raw data, as well as calculating final yield results, and generating a yield report including the calculated final yield data. The method may further comprise deleting data not required for generating the yield report, and calculating percentage of opens and shorts data by package, wherein generating a first pass yield report may further include using the calculated percentage of opens and shorts data.
According to another aspect of the invention, the macro may include computer-executable instructions for formatting the raw data, sorting the formatted data according to type and/or category, deleting data not required for generating the yield report, and sorting the remaining data according to device package type using the software macro. In addition, computer-executable instructions may be provided for creating at least one worksheet in the spreadsheet software application according to device package type using the software macro, calculating final yield data by package, and calculating percentage of opens and shorts data by package using the software macro. The data may be downloaded from one or more databases via a workstream server, and the deleted data may include quality assurance lot information, reliability lot information, returned lot information, correlation summary information, and unwanted test type information.
In accordance with still another aspect of the invention, there is provided a computer system for generating a semiconductor manufacturing test first pass yield report, which includes a spreadsheet software application, means for obtaining data from a workstream database, and a software macro having computer-executable instructions for formatting and sorting the data as well as calculating yield results.
Yet another aspect of the invention includes a software macro for generating a semiconductor manufacturing test first pass yield report in a computer system. The macro includes computer-executable instructions for formatting raw data from a workstream database, sorting the formatted data according to type, sorting the formatted data according to category, deleting data not required for generating the yield report, sorting the remaining data according to package, creating at least one worksheet in the spreadsheet software application according to package, calculating final yield and percentage of opens and shorts data by package. The macro may further include computer-executable instructions for generating a first pass yield report including the calculated final yield and percentage of opens and shorts data, and for providing calculated final yield and percentage of opens and shorts data for each worksheet. In addition, the macro instructions may provide for downloading the raw data from a workstream server or directly from one or more pieces of manufacturing test equipment, such as test handlers and the like.
To the accomplishment of the foregoing and related ends, the invention comprises the features hereinafter fully described and particularly pointed out in the claims. The following description and the annexed drawings set forth in detail certain illustrative aspects and implementations of the invention. These are indicative, however, of but a few of the various ways in which the principles of the invention may be employed. Other objects, advantages and novel features of the invention will become apparent from the following detailed description of the invention when considered in conjunction with the drawings.